The U.S. Supreme Court Monday is scheduled to hear arguments in a key U.S. immigration case challenging President Barack Obama's executive action that delayed the deportation of nearly 5 million undocumented immigrants.

The case, U.S. v. Texas, is about two Obama administration initiatives named Deferred Action for Childhood Arrivals (DACA) and Deferred Action for Parents of Americans (DAPA), which offer protections to immigrants, allowing them to work legally for a period of two years subject to renewal.

The measures would protect young immigrants from deportation if they were brought to the U.S. illegally as children. They would also extend deportation protections to parents of U.S. citizens and permanent residents who have been in the country for some years.

The beneficiaries are people like Teresa Garcia of Seattle, who told the Associated Press that she has been living in the U.S. illegally for 14 years after over-staying her tourist visa. She has an 11-year-old daughter, who is a U.S. citizen, and two sons who are benefiting from DACA protections.

"To have a Social Security number, that means for me to have a better future. When I say better future, we are struggling with the little amount of money my husband is getting for the whole family. It makes for stress every day. We struggle to pay for everything," Garcia told AP.

Her husband is a trained accountant, but is working in construction jobs. Garcia said she would be eager to work "starting right now" if she becomes legally able to do so.

FILE - A Mexican migrant talks to a family member through the border fence between Ciudad Juarez and El Paso, United States, after a bi-national Mass in support of migrants in Ciudad Juarez, Mexico, Feb.15, 2016.

Immigration advocates are planning a demonstration on the same day the U.S. Supreme Court is scheduled to hear arguments by the 26 states that are challenging President Obama's executive action case.

During the “Fight for Families” rally, civil rights leaders, elected officials, and members of the community are expected to hold a news conference on the steps of the U.S. Supreme Court.

“I believe that the SCOTUS will make the right decision. We are also going to be inside [the court] because we want to listen to the oral arguments to report back to our community,” Gustavo Torres, CASA de Maryland executive director, a Latino advocacy group in Maryland, told VOA.

Torres said leaders are very “optimistic,” and the message to immigrants is that “we are going to keep fighting, but now it is in the hands of the Supreme Court.”

Republicans criticized the plan as an illegal executive overreach when Obama announced it on November 2014. The administration argued that the executive branch was within its rights in deciding to defer deportation of selected groups of immigrants.

With Justice Antonin Scalia's unexpected death, the high court will have to proceed with eight justices. A 4-4 vote would mean the lower court’s ruling will stand.

In U.S. v. Texas, the lower court’s ruling means a block on Obama's DAPA and DACA expansion.